One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,5)(3,7,8,6)(9,10,13,14)(11,15,16,12)(17,18,21,22)(19,20,23,24)(25,26,30,34)(27,32,28,31)(29,33,38,37)(35,40,36,39)(2,5)(6,7)(10,14)(12,15)(18,22)(19,23)(25,27,30,28)(26,31,34,32)(29,36,38,35)(33,40,37,39)(3,8)(6,7)(9,11,13,16)(10,15,14,12)(17,19,21,23)(18,20,22,24)(25,28,30,27)(26,32,34,31)(29,36,38,35)(33,40,37,39)(1,3)(2,6)(4,8)(5,7)(9,11)(10,15)(12,14)(13,16)(17,20,21,24)(18,23,22,19)(25,26)(27,32)(28,31)(29,37)(30,34)(33,38)(35,39)(36,40)(1,2)(3,7)(4,5)(6,8)(9,12,13,15)(10,16,14,11)(17,18)(19,20)(21,22)(23,24)(25,29)(26,33)(27,35)(28,36)(30,38)(31,39)(32,40)(34,37)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.